Plastic antifriction material

ABSTRACT

A plastic antifriction material containing a polyimide resin, powdered solid lubricants as fillers, and also polyarylates or aromatic polyamides.

United States Patent [72] Inventors Vasily Vladimirovich Korshak ulitsa Gubkina, 4, kv. 81; Irina Alexandrovna Gribova, ulitsa Vavilova, l2, kv. 31; Alexandr Petrovich Krasnov, prospekt Kalinina, 31, kv. 28; Alla Nikolaevna Chumaevskaya, Leninsky prospekt, 101, korpus 163, kv. 86; Olga Svyatoslavovna Natsarenus, ulitsa Grimau, 13, korpus 2, kv. l5; Svellana Vasilievna Vinogradova, Belyaevo-Bogorodskoe, Kvartal 48-a, korpus 6a, kv. 63; Yakov Semenovich Vygodsky, Leninsky prospekt, 101, korpus 135, kv. 38; Vyacheslav Alexandrovich Pankratov, ulitsa Usievicha, 25, kv. 135; Grigory Lvovich Slonimsky, ulitsa Chkalova, l/4, kv. 16, all 01' Moscow, U.S.S.R.

[21] Appl. No. 835,785

[22] Filed June 23, 1969 [45] Patented Dec. 21, 1971 [54] PLASTIC ANTlFRlCTlON MATERIAL 8 Claims, No Drawings [52] U.S.Cl 252/12 [51] lm. Cl C10m 7/34 [50] Field of Search 252/12, 12.2, 12.4, 12.6

[56] References Cited UNITED STATES PATENTS 2,698,966 1/1955 Stott et al. 252/12 3,122,505 2/1964 Rulon-Miller et al 252/12 3,287,288 11/1966 Reiling 252/12 Primary Examiner--Daniel E. Wyman Assistant Examiner-l. Vaughn Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: A plastic antifriction material containing a polyimide resin, powdered solid lubricants as fillers, and also polyarylates or aromatic polyam ides.

PLASTIC ANTIFRlCTlO N MATERIAL V 4 To preparethe aromatic polyamides used as an antifriction This invention relates to plastic antifriction materials inmaterlal f i afomanc dmmlnes and aromatic dwarf tended for the fabrication of elements of dry-friction assemboxyhc acld chlorides m a etrahydmfuran'wateSoda medlum are subjected to low-temperature olycondensation, fol- 5 lowed by filtering off and drying the resultant polymers.

Plastic antifriction materials derived from polyimide In order to prepare an aljltifriction "i i noted for its plastics filled with solid lubricants, e.g., graphite or molybenhanced thermal and electrical conduiuvlty metal P denum disulfide are known e.g., powdered copper or silver, are incorporated into the blend of the aforesaid components at the mixing step.

blies, such as bearing cages, sliding bearing bushings, and geared transmission components.

When used in dry friction assemblies, this known antifric- Th 1 tion material exhibits a marked increase of its friction coeffie Y tam mouldmg composition winch consists of a cient with the increase of the working temperatures up to finely dlvlded hpmogeneous powder Subjected to ugh-tem- 70l20f C., whiehprecludes the employment of the material perature mouldmg' under the aforesaid conditions, despite its good mechanical above PmFedure ylelds an annfncuonmatenal exhlbn' characteristics mg high mechanical strength, good workability, a stable coef- It an object of the present mvenuon to ehmmate the ficlent of friction over awide temperature range, and superior aforementioned disadvantage. wear reslstanc-e' For a better understanding of the present invention, given hereinbelow are the following examples of preparing the antifriction material.

It is a further and more specific object of the present invention to provide an antifriction material noted for its stable coefficient of friction over'a wide temperature range.

' This object is accomplished by the provision of a plastic an- EXAMPLE 1 tlfriction material derived from a polyimide resin filled with powdered solid lubricants and also containing, according to Dianhydride f diphenyl oxide-3.3. .4-tetracarboxylic the invention, polyarylates or aromatic polyamides. acid and diaminodiphenyl ether taken in a molar ratio of 1:1 Under dry friction conditions when polymer molecules are are subjected to polycondensation in dimethylformamide at a subjected to both thermal effects and mechanical cracking, temperature of 10-25 C. for a period of 4 hours, with conrigid-chain polymers, such as polyarylates or aromatic polyatinuous stirring. The resultant polyamidoacid is precipitated mides, exhibit superior performance characteristics due to with a benzene-acetone mixture taken in a five-fold excess and their less pronounced authohesion properties. dried in a vacuum cabinet at 80 C. for 2 hours. The dry The incorporation of rigid-chain polyarylates or aromatic polyamido acid thus obtained is then polycyclized in vacuo (1 polyamides into a polyimide resin-based antifriction material mm. Hg) at a temperature of 100 C. for 2 hours, at 200 C. exerts a stabilizing effect on the coefficient of friction over a for 3 hours, and at 300 C. for 1.5 hours. wide temperature range. Polycyclization yields a polyimide having the following It is expedient to employ an antifriction material of the folstructural formula 0 0 II II 0. N O r C O u lowing composition, percent by weight: polyimide, 4-78; filler I (solid lubricants), 2-95, and polyarylates or aromatic polya- The Polylmlde l5 tl'llulated oblaln a homogeneous mides, 1-20. powder.

in order to enhance the thermal and electrical conductivity 8- of the Powdered Polylmlde, 450 of Powdered of the present antifriction material, to improve its moldability molybdenum dlsulfide (parlklle Size and 8- of and also to raise its hardness and wear resistance, it is good p l f l' p y y ofthe following Structural formula practice to additionally incorporate thereinto metal powders as fillers.

-78; solid lubricants, 2-75; polyarylates or aromatic polyamides, 1-20, and metal powders, 20-40.

The antifriction material, according to the present invention, is prepared as follows.

Polycondensation of an aromatic diamine with an aromatic O tetracarboxylic acid dianhydride yields a polyamido carboxyli id, hi h, on b i ubj t d t olycyclization gives a are mixed in a vibrating mill for 2 minutes until a homogeneo v 0 7 1n the latter case, the antifriction material should preferably H H V C C() C -O- be of the following composition, percent by weight: polyimide,

polyimide. ous mass is obtained.

The polyimide obtained in the form of a fused mass is The polyarylate having the aforespecified structure is thoroughly ground to prepare a homogeneous powder which prepared from terephthaloyl chloride and phenolphthalein by is then mixed in a vibrating mill with powdered polyarylate or the high-temperature polycondensation technique. The aromatic polyamide and powdered filler (solid lubricant, e.g., process is conducted at a temperature of 220 C. for a period molybdenum disulfide or graphite). The polyarylate o amof 12 hours and comprises stirring, in a stream of argon, a mix matic polyamide used as a component of the antifriction ture of equimolar amounts of the starting compounds dismaterial should have a softening or melting point that lies solved in Sovol(chlorinated biphenyl). close to the temperature at. which the polyimide is being The resultant polyarylate is dissolved in chloroform to obprocessed. tain a 5 percent solution and thereafter precipitated with a The polyarylates employed as an antifriction material comfive-fold excess of methyl alcohol, filtered off and dried at a ponent are prepared from aromatic dicarboxylic acid tempe ature of 12 C- for 6 h urs. chlorides and bisphenols in a high-boiling solvent by the The components are mixed in a vibrating mill to give a equilibrium high-temperature polycondensation method. The moulding composition, which is thereafter moulded at a tempolyarylates thus obtained are precipitated with an excess of perature of 390-4 10 C. and a specific pressure of 1,000 to solvent, filtered off and dried to constant weight. 1,200 kg./cm.".

The antifriction material prepared as disclosed hereinbefore exhibits the following physical and mechanical characteristics:

Brincll hardness. kgjmm. 20 Impact strength. kg./cm./cm. 3 intensity of linear wear IXIO Coefficient of friction 0.12 Maximum working temperature. C. 240

EXAMPLE 2 A Polymide of the general formula derived from diphenyl oxide 3,3',4,4'-tetracarboxylic acid dianhydride and m-phenylene diamine, and a polyarylate of the general formula V M I derived from terephthaloyl dichloride and dihydroxydiphenylfluorene are prepared as disclosed in example 1.

37.5 g. of the powdered polyimide, 12.5 g. of the powdered polyarylate and 450 g. of powdered molybdenum disulfide (particle size, 1-2,u) are mixed in a vibrating mill for a period of 2 minutes to obtain a homogeneous mass.

The moulding composition thus prepared is subjected to moulding at a temperature of 490500 C. and a specific pressure of 1.000 to 1,200 kg./cm.

The antifriction material exhibits the following physical and mechanical characteristics:

Brinell hardness, kg/mm. 21 Impact strength. kg.cm./cm.' 2 Intensity of linear wear 1.3Xl()" Coefficient of linear wear 0.12 Maximum working temperature. C. 260

EXAMPLE 3 Fifty grams of powdered a polyimide prepared as disclosed in example 1 is mixed in a vibrating mill with 420 g. of graphite powder and 20 g. of polymetaphenylene isophthalamide ofthe structural formula Intensity oflinear wear 0.9x 10' Coefficicnt of friction 0.1 Maximum working temperature. C. 250

EXAMPLE 4 37.5 g. of powdered polyimide prepared as disclosed in example 2 is mixed in a vibrating mill for a period of 2 minutes with 450 g. of graphite powder and 12.5 g. of polyamide havl0 ing the structural formula II 0 h 20 the polyamide being synthesized from anilinephthalein and isophthalic acid by the method disclosed in example 3.

The moulding powder thus obtained is moulded at a temperature of 490-500 C. and under a specific pressure of 1,000 to 1,200 kg./cm.

The antifriction material exhibits the following physical and mechanical characteristics:

Intensity oflincar wear 0.9Xl0 Coefficicnt of friction 0.1 Maximum working temperature. C. 270

EXAMPLE 5 37.5 g. of powdered polyimide and 12.5 g. of polyarylate prepared as disclosed in example 1, 325 g. of molybdenum disulftde powder (particle size, l-2y.), and 125 g. of copper powder are blended in a vibrating mill for a period of 2 minutes.

The moulding composition thus obtained is moulded at a temperature of 3904l0 C. and under specific pressure of 1,000 to 1.200 kg./cm.

The antifriction material exhibits the following physical and mechanical characteristics:

Brinell hardness. kgjmm. 24 Impact strength. kg.cm./em. 2.5 Coefficient of friction 0.1 N Maximum working temperature, C. 250

EXAMPLE 6 37.5 g. of powdered polyimide prepared as disclosed in example 1. 12.5 g. of polyamide prepared by the procedure of example 3, 325 g. of molybdenum disulfide powder (particle size. 1-2u), and 125 g. of silver powder are mixed in a vibrating mill for a period of 2 minutes.

The moulding composition thus obtained is subjected to compression moulding at a temperature of 3904l0 C. and under specific pressure of 1,000 to 1,200 kg./cm.

The antifriction material exhibits the following physical and mechanical characteristics:

Brinell hardness. kgJmm. Z2 Intensity of linear wcar (1.7X10 Maximum working temperature. "C. 250

Although the present invention has been described with reference to the preferred embodiment thereof, it will be readily understood by those skilled in the art that various changes and modifications can be practised without departing from the spirit and scope of the invention as disclosed in the description and appended claims.

We claim:

1. An antifriction material having a stable coefficient of friction over a wide temperature range comprising 1. 4 to 78 percent by weight of one or more aromatic polyimide resins prepared by polycondensation of an aromatic diamine with an aromatic tetracarboxylic acid dianhydride to yield a polyamido carboxylic acid which after being subjected to polycyclization gives a polyimide,

2. 2 to 75 percent by weight of one or more solid inorganic lubricants, and

3. l to percent by weight of one or more rigid-chain polymers selected from the group consisting of a) polyarylates prepared by polycondensation of aromatic dicarboxylic acid chlorides and bisphenols and (b) aromatic polyamides prepared by polycondensation of aromatic diamines and aromatic dicarboxylic acids or their chlorides.

2. An antifriction material as in claim 1 which further comprises a powdered metal filler.

3. An antifriction material as in claim 2 which comprises 4 to 78 percent of polyimide resin, 2 to 78 percent by weight of solid lubricants, 20 to 40 percent by weight of powdered metal filler, and l to 20 percent by weight of the polyarylate or aro- 6 matic polyamide polymer.

4. An antifriction material as in claim 1 wherein the polyimide is prepared from diphenyl oxide 3,3, 4, 4-tetracarbox' ylic dianhydride and a diamine selected from the group consisting of 4,4-diaminodiphenyl ether and m-phenylenediamine.

5. An antifriction material as in claim 1 wherein the polyarylate is prepared from terephthaloyl chloride and a bisphenol selected from the group consisting of phenolphthalein and dihydroxydiphenyl fluorene.

6. An antifriction material as in claim 1 wherein the polyamide is prepared from isophthaloyl dichloride and an amine selected from the group consisting of m-phenylenediamine and anilinephthalein.

7. An antifriction material as in claim 1 wherein the solid lubricant is selected from the group consisting of molybdenum disulfide and graphite.

8. An antifriction material as in claim 2 wherein the metal is copper or silver. 

2. 2 to 75 percent by weight of one or more solid inorganic lubricants, and
 2. An antifriction material as in claim 1 which further comprises a powdered metal filler.
 3. 1 to 20 percent by weight of one or more rigid-chain polymers selected from the group consisting of (a) polyarylates prepared by polycondensation of aromatic dicarboxylic acid chlorides and bisphenols and (b) aromatic polyamides prepared by polycondensation of aromatic diamines and aromatic dicarboxylic acids or their chlorides.
 3. An antifriction material as in claim 2 which comprises 4 to 78 percent of polyimide resin, 2 to 78 percent by weight of solid lubricants, 20 to 40 percent by weight of powdered metal filler, and 1 to 20 percent by weight of the polyarylate or aromatic polyamide polymer.
 4. An antifriction material as in claim 1 wherein the polyimide is prepared from diphenyl oxide 3,3'', 4, 4'' -tetracarboxylic dianhydride and a diamine selected from the group consisting of 4,4''-diaminodiphenyl ether and m-phenylenediamine.
 5. An antifriction material as in claim 1 wherein the polyarylate is prepared from terephthaloyl chloride and a bisphenol selected from the group consisting of phenolphthalein and dihydroxydiphenyl fluorene.
 6. An antifriction material as in claim 1 wherein the polyamide is prepared from isophthaloyl dichloride and an amine selected from the group consisting of m-phenylenediamine and anilinephthalein.
 7. An antifriction material as in claim 1 wherein the solid lubricant is selected from the group consisting of molybdenum disulfide and graphite.
 8. An antifriction material as in claim 2 wherein the metal is copper or silver. 